(5) CK Ingold,“Structure and Mechanism in Organic Chemis-Book Co., Inc, New York, 1940, pp. 184-206. try,” Cornell University Press, Ithaca, NY, 1963, pp. 474-480. ing groups which are involved in molecular rearrangements. We have obtained considerable quantitative information in this respect by the use of radioactive with results indicating the expected. preference for migration of those groups which are, presumed to be better electron donors ...